Re: SDL::Surface::new_from and PLot question

On Mon, Nov 16, 2009 at 1:54 PM, Kartik Thakore <[email protected]>wrote:

> Hi,
>
> So I fixed new_from to prevent it from segfaulting. Now as for direct write
> from PLot to Surface, where can I see the how the raw data is stored and
> made acessible in PDL.
>
> Kartik Thakore
>

Kartik -

I've never looked too closely at the internals of PDL to know precisely how
it stores the data, but as I understand, the data is typically stored in a
packed scalar.  The proper way to get at this data is using the get_dataref
and upd_data member functions.  These functions are discussed here:
http://search.cpan.org/~chm/PDL-2.4.5/Basic/Core/Core.pm.PL#get_dataref

For the PDL folks, who probably don't know what's going on, I am trying to
make PLplot play with SDL.  I would like to quickly draw animations of
plots.  Doug wrote an option into PLplot that allows it to plot to a memory
location, and PDL::Graphics::PLplot is capable of specifying a piddle for
this purpose.  His original intention was to allow him to load an image into
a piddle and overlay a graph.  My intention is to make an SDL surface that
uses the same memory location as a PLplot output, so that I can use SDL's
quick redrawing mechanisms for fast interactive plotting.  I don't actually
need to get PDL involved in this - SDL would do well to interact directly
with PLplot - but it's probably a good idea to interface SDL::Surfaces with
PDL while we're at it.

David